package com.etone.smartAudit.utils;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.MessageDigest;

public class AESUtil {

    /***
     * AESEcb加密
     * @param data
     * @param key
     * @return
     */
    public static String aesECB(String data, String key) {

        return AES_Encrypt(data, key, "ECB");
    }

    /**
     * AES加密
     *
     * @param plaintext   明文
     * @param Key         密钥
     * @param EncryptMode AES加密模式，CBC或ECB
     * @return 该字符串的AES密文值
     */
    public static String AES_Encrypt(Object plaintext, String Key, String EncryptMode) {
        String PlainText = null;
        try {
            PlainText = plaintext.toString();
            if (Key == null) {
                return null;
            }
            Key = getMD5(Key);
            byte[] raw = Key.getBytes("utf-8");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/" + EncryptMode + "/PKCS5Padding");
            if (EncryptMode == "ECB") {
                cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
            } else {
                IvParameterSpec iv = new IvParameterSpec(Key.getBytes("utf-8"));//使用CBC模式，需要一个向量iv，可增加加密算法的强度
                cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
            }
            byte[] encrypted = cipher.doFinal(PlainText.getBytes("utf-8"));
            String encryptedStr = new String(new BASE64Encoder().encode(encrypted));
            return encryptedStr;
        } catch (Exception ex) {
            System.out.println(ex.toString());
            return null;
        }
    }

    /**
     * AES解密
     *
     * @param cipertext   密文
     * @param Key         密钥
     * @param EncryptMode AES加密模式，CBC或ECB
     * @return 该密文的明文
     */
    public static String AES_Decrypt(Object cipertext, String Key, String EncryptMode) {
        String CipherText = null;
        try {
            CipherText = cipertext.toString();
            // 判断Key是否正确
            if (Key == null) {
                //System.out.print("Key为空null");
                return null;
            }
            Key = getMD5(Key);
            byte[] raw = Key.getBytes("utf-8");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/" + EncryptMode + "/PKCS5Padding");
            if (EncryptMode == "ECB") {
                cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            } else {
                IvParameterSpec iv = new IvParameterSpec(Key.getBytes("utf-8"));//使用CBC模式，需要一个向量iv，可增加加密算法的强度
                cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
            }
            byte[] encrypted1 = new BASE64Decoder().decodeBuffer(CipherText);//先用base64解密
            //byte[] encrypted1 = CipherText.getBytes();
            try {
                byte[] original = cipher.doFinal(encrypted1);
                String originalString = new String(original, "utf-8");
                return originalString;
            } catch (Exception e) {
                System.out.println(e.toString());
                return null;
            }
        } catch (Exception ex) {
            System.out.println(ex.toString());
            return null;
        }
    }

    /**
     * 进行MD5加密
     *
     * @param s 要进行MD5转换的字符串
     * @return 该字符串的MD5值的8-24位
     */
    public static String getMD5(String s) {
        char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

        try {
            byte[] btInput = s.getBytes();
            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            // 使用指定的字节更新摘要
            mdInst.update(btInput);
            // 获得密文
            byte[] md = mdInst.digest();
            // 把密文转换成十六进制的字符串形式
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str).substring(8, 24);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}